The past perfect tense is utilized to describe an event that occurred before another past action. It is constructed with "had" followed by the past participle of the verb. In forming questions, the subject and "
We use past perfect to talk about something that happened before another action in the past
FORM
EXAMPLES
INTERROGATIVE: Had they arrived?
NEGATIVE: She hadn't asked
AFIRMATIVE: She had given
The past perfect is formed using had + past participle. Questions are indicated by inverting the subject and had. Negatives are made with not. SUJETO + HAD + PAST PARTICIPLE
CONTRAST BETWEEN PAST PERFECT SIMPLE AND PASTE SIMPLE
These two tenses are both used to talk about things that happened in the past. However we use past perfect to talk about something that happened before another action in the past, which is usually expressed by the past simple. For example: "I had already eaten my dinner when he called."